[tor-bugs] #18479 [Tor]: Avoid overflow in tor_timegm when time_t is 32 bit

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#18479: Avoid overflow in tor_timegm when time_t is 32 bit
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 Reporter:  teor                             |          Owner:
     Type:  defect                           |         Status:
 Priority:  Medium                           |  needs_revision
Component:  Tor                              |      Milestone:  Tor:
 Severity:  Normal                           |  0.2.8.x-final
 Keywords:  integer-overflow security-maybe  |        Version:  Tor:
Parent ID:                                   |  unspecified
 Reviewer:                                   |     Resolution:
                                             |  Actual Points:
                                             |         Points:
                                             |        Sponsor:
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Changes (by nickm):

 * status:  needs_review => needs_revision


Comment:

 NM.1. I'm not sure how I feel about this line:
 {{{
 +  tor_assert(seconds >= TIME_MIN);
 }}}

 Are we sure that nobody can ever give tor_timgm() a big negative tm_year,
 causing it to crash Tor?

 NM.2. I think it would make more sense to make sure that `*time_out` is
 always set to _something_, in case some foolish programmer ignores the
 return value?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18479#comment:2>
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